Depends a lot on the design of the plunger. I had a plunge lock knife (an expensive one at that) fail on me repeatedly due to fracturing of the plunger assembly. Eventually it was fixed by the maker (they had removed a little bit too much material inside the spring cup).
On the bright side, if it fails, it'll probably fail in the locked open position. If you haven't heard about rampant failures, then the design is probably good and you have nothing to worry about. I've never heard of a plunger failure on a MT Halo, and those get subjected to a lot of opening shock compared to a side opener.
!